61_ 



3.3.1 REMOTS® Sediment-Profile Photography 



Data collected from the thirteen REMOTS® camera stations indicated the presence of 

 a uniform grain size distribution within all three of the CLIS reference areas. The 

 REMOTS® photographs obtained at randomly selected stations within the CLIS-REF, 

 2500W, and 4500E reference areas display a major modal grain size of >4 phi, consistent 

 with ambient central Long Island Sound sediment. All three reference areas appear to be 

 free from dredged material, with no evidence of errant disposal in any of the replicate 

 photographs. 



Reference areas 4500E and CLIS-REF exhibited the characteristics of a well- 

 established, relatively undisturbed environment in Long Island Sound. However, 

 REMOTS® photographs obtained at 2500W showed evidence of heavy trawling dismrbances 

 (Figure 3-28 A). The action of the trawl net and tickle chains across the bottom scoured the 

 oxidized surface layer of sediment and displaced the surface and shallow-dwelling 

 organisms. As a result, both the RPD and OSI values for 2500W were lower than expected, 

 with means of 0.62 cm and 5.75, respectively (Appendix A, Table 12). Apparently, Stage I 

 assemblages were quick to recover, and deep burrowing Stage III organisms were unaffected 

 by the surface disturbance (Figure 3-28B). However, Stage II organisms were absent at 

 three of four REMOTS® stations. 



At reference area 4500E, Stage III assemblages were present at all REMOTS® 

 stations, with Stage I and Stage II organisms present at three of the four. The replicate- 

 averaged RPD depths ranged from 0.77 cm at STA 4 to 0.97 cm at STA 1 . A mamre 

 benthic assemblage and moderate RPDs yielded median OSI values of 6.0 for all four 

 REMOTS® stations. The replicate-averaged RPD depths for CLIS-REF ranged from 

 0.64 cm at the western-most station (STA 4) to 2.7 cm at STA 2 (Appendix A, Table 12). 

 The biological diversity of the area was intact with Stages I, II, and III represented at all 

 five REMOTS® stations. The deep RPD depths and a diverse benthic community elevated 

 the OSI values. Median OSI values ranged from 4.0 at STA 3 to 8.0 at STA 1 and STA 2 

 with an overall mean RPD of 1.37 cm. 



There was no evidence of redox rebound intervals or methane gas in any reference 

 area REMOTS® photograph. However, conditions indicating low dissolved oxygen 

 conditions were detected in one replicate within 2500W, a direct result of the recent surface 

 dismrbance. Sediment surface layer roughness was predominantly classified as physical at 

 2500W, 4500E, and CLIS-REF. Boundary roughness values for the three reference areas 

 ranged from 0.73 cm at CLIS-REF to 2.87 cm at 2500W (Appendix A, Table 12). 



Monitoring Cruise at the Central Long Island Sound Disposal Site, July 1994 



